Directional antennas are known in the art and a variety of different types thereof have been developed; however, such antennas are commonly of a substantial size and/or complexity. An exception to the foregoing is the end loaded filament antenna of U.S. Pat. No. 3,605,097 which may, for example, be employed as a vertically polarized element of the present invention.
Direction finding antennas are commonly comprised as arrays of stub type antennas for vertically polarized signals and rather large spiral antennas for circularly polarized signals. Difficulties are generally encountered in attempts to achieve direction finding capabilities at low microwave frequencies, such as radiation below 2 GHz and stub antennas have very limited bandwidth. In addition many applications of direction finding antennas require the mounting of same upon aircraft so that large size is a serious drawback.